The pain is too raw for Tina Bayliss to ponder whether new family violence initiatives announced yesterday may have prevented her teenage daughter's murder.

"It's a scenario that is very difficult to think, that if I'd done something different, she's still be alive."

However, she welcomed the raft of changes revealed by Prime Minister John Key that aimed to reduce family violence, which included giving partners greater access to people's criminal histories.

"It's taken a hell of a long time. It's three years in November since Jade was murdered."

Four days before Jeremy McLaughlin strangled her daughter, Jade, 13, while she was home sick from school in Christchurch in November 2011, Bayliss had visited police to question whether he had a criminal past.

They told her nothing but gave her a trespass notice, telling her to use that to order McLaughlin off her property if he stalked her.

After the murder, she discovered he had been convicted of manslaughter in Australia for being part of a group that brutally killed Perth teenager Phillip Vidot 16 years earlier.

"I still don't know if police had anything on their screens that they could have told me."

She believed New Zealand needed a register for serious criminals to protect everyone rather than only sharing information with their worried partners.